Danny Pintauro, 39, starred in the 1980s sitcom "Who's the Boss?" Last year he married Wil Tabares, and recently he revealed that he has been HIV-positive since 2003.

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Pintauro played Angela Bower's son, Jonathan, in "Who's the Boss?" Angela Bower was played by Judith Light.

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Jonathan Taylor Thomas turned 34 on Tuesday, September 8, and fans are wishing they could see him more. He pops up occasionally, like on "Home Improvement" co-star Tim Allen's ABC series "Last Man Standing," which feels like deja vu all over again.

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Thomas (at right with Zachery Ty Bryan, left, and Taran Noah Smith) first snagged hearts as one of the sons on Allen's hit '90s show.

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The late Steve Irwin's daughter, Bindi Irwin, has grown up to be quite the conservationist, just like her dad. She's also become a bit of a celeb like her father and was recently recruited for season 21 of "Dancing With the Stars."

Matthew Lewis, who starred as the shy and unassuming Neville Longbottom in the "Harry Potter" movies, has grown into a strapping young man. He buffed up for roles as a soldier in "Bluestone 42" and an athlete in "Me Before You."

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Lewis sported a slightly different look as Neville in the "Harry Potter" films.

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Along with her "Harry Potter" co-star Lewis, Emma Watson's proving that she's not little Hermione anymore. The actress played a thief in 2013's "The Bling Ring" and an ax-carrying marauder in "This Is the End."

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A young Watson as frizzy-haired Hermione in "Harry Potter."

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Daniel Radcliffe's development has been watched by millions as he came of age in the "Harry Potter" movie franchise, which launched when he was 12. By 2007, Radcliffe was ready to show how grown-up he'd become, starring in "Equus" -- a stage production that required some nudity.

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As a child, Radcliffe may have become the world's favorite wizard as "Harry Potter."

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Jaden Smith has grown up since his breakout role with his dad, Will, in "The Pursuit of Happyness." Although he once again starred with his father in 2013's "After Earth," Jaden isn't a kid anymore.

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Smith was a baby-faced child star in 2006's "The Pursuit of Happyness."

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Jayden's sister, Willow, has followed her big brother into show business. In 2011, she had a hit single with "Whip My Hair."

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Smith appeared with her dad in the 2007 film "I Am Legend."

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Fans were excited to see a grown-up Haley Joel Osment in the "Entourage" movie in 2015.

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Osment first found fame as as the child star of 1999's "The Sixth Sense."

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Tyler Posey appeared on Fox's Teen Choice Awards in August 2014 in Los Angeles with Jennifer Lopez. It was a throwback to years earlier when ...

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Posey co-starred with Lopez in "Maid in Manhattan" in 2002.

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Keke Palmer became the first black Cinderella on Broadway in 2014. She's worked steadily through most of her childhood.

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Palmer got her first major role in "Akeelah and the Bee" in 2006.

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Angus T. Jones, left, grew up before viewers' eyes on the hit CBS series "Two and a Half Men."

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Jones was a chubby-cheeked youth in 2003 at the premiere of his movie "Bringing Down the House."

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Justin Bieber is now in his 20s and, according to his mentor Usher, still growing up. But between the tattoos, the vandalism accusations and a recent arrest, Biebs is not the same "Baby" singer we met in 2009.

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Back then, Bieber was a fairly innocent teen heartthrob.

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Twerking Miley Cyrus (with Robin Thicke during the 2013 MTV Video Music Awards at in New York) was a far cry from the child star many remembered.

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In 2006, Cyrus was known as the star of Disney's "Hannah Montana."

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Selena Gomez's appearance hasn't changed dramatically since she starred on the Disney Channel's "Wizards of Waverly Place," but her work sure has. Gomez has stretched herself with more mature content, such as the risqué movie "Spring Breakers" and her suggestive single "Come and Get It."

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Gomez was still a youngster in 2007 when she attended the premiere of Walt Disney's "Pirates Of The Caribbean: At World's End."

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Vanessa Hudgens has appeared in more adult projects such as "Spring Breakers" and "Machete Kills."

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Hudgens came to fame as a Disney Channel star in 2006 but soon stepped away from her wholesome "High School Musical" roots.

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Oh, how you have grown, Zac Efron. The "High School Musical" star is now appearing in more adult roles, including 2015's "We Are Your Friends."

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His fans will still always remember him as the fresh-faced Troy Bolton in the "High School Musical" franchise.

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Keshia Knight Pulliam held a pretty iconic role as a youngster, but these days, she is all grown up and appearing in TV movies like "The Love Letter."

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Pulliam will always be remembered as Rudy Huxtable on "The Cosby Show."

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Raven-Symone now has a gig as one of the co-hosts on "The View."

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Her breakout role as Olivia on "The Cosby Show" led to her very successful Disney series "That's So Raven."

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Alyssa Milano starred as a preteen on the '80s series "Who's the Boss?" but also had a hit as an adult with "Charmed."

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Milano's role as Samantha Micelli, the daughter of a former athlete who accepts a job as a housekeeper for an advertising executive with a young son on "Who's the Boss?" first made her a star.

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Macaulay Culkin turned a scream and an exaggerated expression into a blockbuster movie franchise when he starred in 1990's "Home Alone" at the age of 10. He went on to star in 1991's "My Girl," but in recent years, he has not been a huge fan of being on camera. In April 2013, he ripped into paparazzi in the United Kingdom for trying to take his photo.

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His "Home Alone" films are just as popular now as they were in the 1990s.

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"Mad Men" fans have watched Kiernan Shipka grow up as Sally, the daughter of protagonist Don Draper. Having starred on the series since she was 7, Shipka's gone from being a little ballerina with a lisp to a teen girl with enviable poise.

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Shipka as a youngster when she first snagged the role of Sally on "Mad Men."

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One minute, Abigail Breslin was a 10-year-old "Little Miss Sunshine," and the next thing we know, she's flashing her bra in 2011's "New Year's Eve." The actress is now grown-up enough to take on the older sister role, as she did in the 2013 release "Ender's Game." She also nabbed a role in the 2015 TV series "Scream Queens."

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Many still remember the actress as Olive Hoover in the 2006 film "Little Miss Sunshine."

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Designers Mary-Kate Olsen, left, and Ashley Olsen are a force to be reckoned with in the fashion world.

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The Olsen twins have been in the entertainment industry since they were literally in diapers; the pair took turns playing Michelle Tanner on "Full House" from 1987 to 1995. They went on to star in their own movies before starting their fashion lines, Elizabeth and James and The Row.

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These days, Jonathan Lipnicki is old enough to play Renee Zellweger's love interest.

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He's best known for his role as Zellweger's cute-beyond-words son in 1996's "Jerry Maguire."

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Chloë Grace Moretz was a "Kick-Ass" actress even as a kid. She outgrew her baby look but not her action moves: The star appeared in the "Kick-Ass" sequel in 2013.

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As a child, Moretz also had starring roles in movies like "The Amityville Horror," which she appeared in at age 8.

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Dakota Fanning has appeared in so many movies and TV shows since age 6 that we could put together her baby book. She's now not only an acclaimed actress but also a model.

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Fanning was quite the tyke on "The Tonight Show with Jay Leno" in 2002.

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Nowadays, Lindsay Lohan is known more for troubles than for her career.

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Lohan showed off her acting prowess at 12 when she played a set of identical twins in the 1998 remake of "The Parent Trap." She went on to star in movies like "Freaky Friday" (2003) and "Mean Girls" (2004), but her tumultuous private life soon interfered with her career.

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Anna Chlumsky landed a hit comedy with HBO's "Veep" and welcomed her first child in 2013.

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Chlumsky became a star at age 11 thanks to her role in 1991's "My Girl."

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Story highlights

Daniel Pintauro has been HIV-positive since 2003

The "Who's the Boss?" star reveals his status during an interview with Oprah Winfrey

(CNN)"Who's the Boss?" star Danny Pintauro revealed that he's HIV-positive in an interview with Oprah Winfrey that aired on Saturday. He was diagnosed with the infection in 2003.

Pintauro, who played the precocious son Jonathan Bower on the long-running '80s sitcom, shared his secret with Winfrey on her network's "Where Are They Now?" show.

"I wanted to tell you this a long time ago, but I wasn't ready," Pintauro told Winfrey. "I'm ready now. I'm HIV-positive and I have been for 12 years."

Pintauro, 39, came out publicly as a gay man in 1997 after he said a tabloid reporter told him he would be outed with or without his consent.

The diagnosis came in 2003 after a regular checkup. "You know, as a responsible gay man, you're getting an HIV test done every six months."

The news came with a "weird combination of feelings," Pintauro told Winfrey.

"There's this awful feeling of 'I'm never going to be able to have a good relationship, no one's every going to want me.' That was there and that was prevalent. You know, that moment of 'Oh God, I'm now going to have that conversation every time I meet someone. Who's going to want to love me?'"

Fortunately, Pintauro's fears didn't stop him from finding happiness. He married his husband, Wil Tabares, in 2014.

Pintauro posted a photo with Tabares to Instagram on Saturday, apparently referring to his public announcement: "Last meal as a nobody. ;) first meal as an activist. #lifelovelive."